Breakthroughs (The Great War, Book Three)
Harry Turtledove
Timeline-191 (4)
Diamond Mask
Julian May
Galactic Milieu Trilogy (2)
Owls to Athens
Hellenic Traders (4)
Cast in Time Book 2: Baron of the Middle Counties
Ed Nelson
Cast in Time (2)
Wizard
Laurence Mark Janifer
Occasion for Disaster
Randall Garrett & Laurence M. Janifer